1. Field of the Invention
The present invention relates to transmission devices for locks with changeable lock core assemblies and, more particularly, to transmission devices for locks with changeable lock core assemblies which allow easy, smooth operation during change of the lock core assemblies and which are simple in structures, easy in installation, and low in cost.
2. Description of the Related Art
Generally, locks include different types of structures responsive to different needs and different users, e.g., lever locks, trumpet locks, auxiliary locks, etc., wherein the lever locks and the trumpet locks are primary locks while the auxiliary locks provide further security in addition to the lever locks and the trumpet locks.
The lock core assemblies of traditional locks cannot be dismantled. FIGS. 1 and 2 of the drawings illustrate a conventional lever lock in which rotation of either handle "A" causes rotation of a wing-like driving member "C" of a tubular member "B", which, in turn, causes retraction or protruding movement of a latch bolt via transmission of an actuating member "D", thereby locking or unlocking the door to which the lever lock is mounted. The lock core assembly of the lever lock cannot be dismantled. Trumpet locks include similar structures and, therefore, the lock core assemblies thereof are also undetachable.
For safety consideration, house renters and hotel managers often change the locks after the previous tenants and guests have returned the keys, thereby improving security and preventing burglary and theft invents. Yet replacement of the whole lock is time-consuming. In addition, frequent replacements result in a decrease in the life-periods of the locks.
FIG. 3 of the drawing illustrates a conventional auxiliary lock which is commonly used in important departments of public places. However, same problems exist, especially in the case of transfer or resignation of the staff or there is a change in the employees in which all of the locks in the working area must be changed periodically, thereby avoiding loss of property due to unauthorized copying of the keys.
In view of the above-mentioned problems, locks having changeable lock core assemblies have been developed to meet the needs of different users, in which a lock core assembly can be removed from or inserted into the lock via a front side of the lock without detachment of any other elements of the lock. Generally, a lock with a changeable lock core assembly requires two keys, one of which can be operated to open or close the door to which the lock is mounted, while the other one of which is specifically used for change of the lock core assembly. However, it is found that a positioning protrusion of a transmission device of the lock cannot be effectively positioned after removal of the lock core assembly. More specifically, the positioning protrusion cannot be aligned with a hole of the lock core assembly during installation as the former is deviated by an angle or inclined, or due to rotation of either handle. Therefore, manufactures often annex a pushing rod to the packaged lock for users such that the user may use the pushing rod to push the positioning protrusion to a position in alignment with the hole of the lock core assembly for installation of the later. Nevertheless, it is still inconvenient for users.
Therefore, there has been a long and unfulfilled need for an improved lock with a changeable lock core assembly which mitigates and/or obviates the above-mentioned problems.